Installing most things on Debian is sinfully easy:
install package-name. Sadly Java is an exception since it's
not in the basic debian system. I recently downloaded and installed
java 1.5 (or 5, or whatever they're calling it these days) on my
Debian Sid desktop. In brief
the procedure is.
# apt-get install java-package download the sun jdk from java.sun.com # make-jpkg jdk-1_5_0-linux-i586.bin # dpkg -i sun-j2sdk1.5_1.5.0_i386.deb # apt-get install sun-j2sdk1.5debian # update-alternatives --config java
(This is what I did. It worked for me, but it may not be the best way or work for you.)
Now the gory details. To make a java install into a debian package you need a tool that will debianize the sun install program. There's a few scripts out there that will do this and I've had the devil of a time finding out which one is the right one to use (I've done the install several times with different ones). It seems like the best choice is probably java-package which is available in Sid. (An alternative was j2se-package, but this is now obsolete.
Download the installer from Sun, you need the one that ends in ".bin" - don't use the RPM.
Once you have the binary you can now debianize it with the make-jpkg commands on the binary file.
When I did this (with all three scripts) I got a problem because the scripts aren't currently set to recognize the file name of the java 1.5 binary from sun (this may well be fixed by the time you read this.) To fix it I edited /usr/share/java-package/sun-j2sdk.sh. (If you can't see how, wait until it gets updated.) After the edit the deb package built with no problem.
With the package built I moved it to where I keep my custom packages (/root/debs) and ran dpkg to install it. It gave an error saying it failed to install due to a dependency on sun-j2sdk1.5debian. However don't panic - if you then install sun-j2sdk1.5debian with apt-get everything installs properly. You can't do this the other way around because sun-j2sdk1.5debian is dependent on sun-j2sdk1.5.
If you had java installed like this before, typing 'java' at the command line just gives you the old VM. To get the new one use update-alternatives (or you can just make your own link).
My thanks to Michael Schuerig for letting me know about newer packaging scripts. I recently found this description of the install process which looks much better than what I have here.
Dirk Estievenart told me about a few things that were out of date. Here is his install procedure:
//download bin jdk from Sun #apt-get install java-package //exit root and login with normal user: #fakeroot make-jpkg jdk-1_5_0_06-linux-i586.bin //su again: #dpkg -i sun-j2sdk1.5_1.5.0+update06_i386.deb #update-alternatives --config java # java -version //The latter just to check